Equalizer Design Research Articles

Comparing fatigue and ultimate loads of two- and three-bladed 20 MW floating offshore wind turbines

Abstract Two-bladed turbines could reduce costs in the whole turbine’s life cycle. Yet, the wind loads are less well distributed, and the rotor does not have the calm inertia of a rotating plate, like a three-bladed turbine. This paper should serve as a numerical basis to understand how different loads of large 20MW floating two- and three-bladed turbines actually are to enable a better estimation of implications from these loads. The most surprising finding is that the tower base bending loads do not increase for the floating two-bladed turbine compared to the floating three-bladed reference. The main tower excitation, known as the blade-passing frequency, happens two- instead of three times per revolution for a two-bladed turbine. For bottom-fixed turbines, an operation with the tower eigenfrequency close to this excitation causes severe loads, which is more likely for a two-bladed turbine. For most floating turbines, the tower eigenfrequency is much higher and happens to be in a bandwidth that serves two-bladed turbines better than three-bladed ones. However, it was also observed that the issue of tower resonance might, in general, be less critical for floating turbines due to a vast increase in tower damping. The highest increase in loads has been found at the tower top if no load alleviation concept, e.g. a teetering hinge or free-yaw, is utilized. Yaw and main bearing loads did not show any significant increase. The unique parked T-position exhibited a major benefit in storm conditions. The final results indicate that large floating two-bladed wind turbines may offer a valuable economic advantage when compared to three-bladed turbines of equal design maturity.

Thermal equalization design for the battery energy storage system (BESS) of a fully electric ship

The adoption of fully electric ships represents a significant step forward in addressing the environmental challenges of climate change and pollution in the shipping industry. This research details the optimized design of a battery energy storage system (BESS) and its air-cooling thermal management system for a 2000-ton bulk cargo ship. In comparison to the conventional flow splitter (FS-I), which divides airflow into 8 transverse branches, two novel designs—FS-II (dividing airflow into 2, 4, and 8 branches) and FS-III (dividing into 2, 4, 8, and 16 longitudinal and transverse branches)—were introduced. FS-II improves flow uniformity from 0.42 (FS-I) to 0.86 but results in an increased pressure drop up to 881.47 Pa. FS-III further enhances flow uniformity to 0.97 while reducing pressure drop to 191.99 Pa. The thermal performance of battery boxes with FS-I, FS-II, and FS-III was evaluated under extreme conditions and a complete voyage cycle. FS-III exhibited superior thermal regulation, maintaining Tmax consistently below 33.9°C during the entire voyage. These findings provide valuable insights for designing thermal management systems in electric ships.

Addressing the Digital Divide in Health Education: A Systematic Review.

The disparity in access to essential healthcare resources and services is exacerbated by the digital divide, which presents a significant obstacle to health education. Effective tactics to advance digital equity and provide equitable access to resources for telehealth and digital health are needed to close this gap. Digital databases such as PubMed, MEDLINE, Scopus, Web of Science, and Google Scholar were used to conduct a systematic review. Keywords and Boolean operators including "digital divide," "health education," "digital equity," "telehealth," "digital health literacy," and "strategies" were used in the literature search process. Only peer-reviewed English-language papers that addressed methods for bridging the digital divide in health education were accepted after being screened in accordance with the preset inclusion and exclusion criteria. The results were compiled using a narrative synthesis method after data were retrieved and synthesized with the aid of suitable quality assessment tools. After satisfying the inclusion criteria, seven papers were added to the systematic review. The results emphasized the complexity of the digital divide in health education and provided a range of approaches to mitigate disparities in access to digital health technologies and resources. The importance of digital equality and universal design, continuous intervention evaluation and monitoring, and enduring obstacles to Internet access and healthcare technology availability were among the major themes. This systematic study emphasizes how critical it is to put evidence-based tactics into practice in order to close the digital divide in health education. Through the promotion of universal design principles, ongoing evaluation of treatments, and digital equity, stakeholders can mitigate health disparities, improve population health, and guarantee equitable access to telehealth and digital health services.

The effect of Philosophy for Children (P4C) activities on the development of moral perception and social rules of preschool children

The purpose of the study was to examine the effects of P4C implementations on children's perceptions of moral and social rules. The study was carried out with a total of 48 children aged five years old, 23 of them in the experimental group and 25 of them in the control group, attending a public school in the 2023–2024 academic years. A quasi-experimental design was used in the research, and the fully mixed sequential equal status design, one of the mixed research typologies, was applied. The Preschool Children's Conceptions of Moral and Social Rules Scale was applied in the quantitative dimension of the research, and observation, interviews, and anecdotal records constituted the qualitative data collection dimension. Briefly, after the implementation process, the experimental group's perception of moral and social norms improved. In the current study, a substantial difference between the children's moral rule and social rule perceptions after the P4C sessions was discovered when the experimental group's moral rule and social rule perception scale scores were analyzed before and after the implementation. A noticeable improvement in cognitive and social-emotional development was seen. It was determined that positive behaviors improved, particularly in moral situations requiring tolerance, in the experimental group. The study came to the conclusion that teaching children philosophy helps them enhance their critical thinking skills.

Brief transition-focused education for families of autistic youth: preliminary mixed-methods investigation

Purpose The transition to adulthood is one of the most challenging and complex processes for autistic youth and their families. Few evidence-based transition support programs exist, and those that have garnered support require long-term commitments and resources that may prohibit participation by families with financial and time limitations. The current study investigated the feasibility and initial promise of a brief, caregiver-focused educational transition program for families of autistic youth delivered in the community over a single day. Methods Quantitative informant-report and qualitative interview data were collected from 12 caregivers of autistic youth before and after program participation. Using a partially mixed sequential equal status design, quantitative and qualitative data were integrated to evaluate change in caregiver transition knowledge and empowerment, as well as caregivers’ perceptions of program feasibility, acceptability, and usefulness. Results Caregivers reported significant increases in knowledge of transition-related topics and sense of empowerment regarding their family life. Caregiver perceptions of the intervention suggest they found it feasible, acceptable, and useful. Conclusions Short-term transition programming may be a helpful option for caregivers who seek transition supports for autistic youth.

Optimal design of RBFNN equalizer based on modified forms of BOA

Optimal design of RBFNN equalizer based on modified forms of BOA

WASTEWATER TREATMENT DESIGN OF KAMPAR STATE POLYTECHNIC CPO PURIFICATION LABORATORY

Kampar Polytechnic has a miniplan laboratory for processing CPO into cooking oil, biodiesel, and soap. During its operation, this processing produces liquid waste and solid waste. The waste released must be treated before being discharged into the environment, provided that the amount of COD reduction efficiency is good enough (63,41%). The COD content in wastewater is still above environmental quality standards. To reduce COD according to permissible standards, recycling is carried out with effluent from the sedimentation process returned to the equalization unit. The design of equalization, coagulation, and flocculation tubs has been successfully carried out. The results obtained are the dimensions of the equalization bath at 2m length, 2m width, and 1.2m height. The dimensions of the coagulation bath are 1.5m long, 1.0m wide, and 1.2m high. The dimensions of the flocculation bath are 2.5m long, 1.5m wide, and 1.2m high, with the provision that consideration meets the volume of liquid waste treated.

Coherent equalization of linear quantum systems

This paper introduces a H∞-like methodology of coherent filtering for equalization of passive linear quantum systems to help mitigate degrading effects of quantum communication channels. For such systems, which include a wide range of linear quantum optical devices and signals, we seek to find a near optimal equalizing filter which is itself a passive quantum system. The problem amounts to solving an optimization problem subject to constraints dictated by the requirement for the equalizer to be physically realizable. By formulating these constraints in the frequency domain, we show that the problem admits a convex H∞-like formulation. This allows us to derive a set of suboptimal coherent equalizers using J-spectral factorization. An additional semidefinite relaxation combined with the Nevanlinna–Pick interpolation is shown to lead to a tractable algorithm for the design of a near optimal coherent equalizer.

Design of coherent passive quantum equalizers using robust control theory

The paper develops a methodology for the design of coherent equalizing filters for quantum communication channels. Given a linear quantum system model of a quantum communication channel, the aim is to obtain another quantum system which, when coupled with the original system, mitigates degrading effects of the environment. The main result of the paper is a systematic equalizer synthesis algorithm which relies on methods of state–space robust control design via semidefinite programming.

Recording media configurations for double-layered bit-patterned magnetic recording

The current magnetic recording technology is approaching its recording density limit. Recently, concepts focused on vertically stacking multiple recording media have gained momentum, driven by the potential to significantly expand recording density. The key challenge for such a system involves methods capable of efficiently separating data originating from the upper and lower layers within a single readback signal. To address this challenge, we first propose two distinct configurations of recording media in bit-patterned magnetic recording (BPMR) system with double recording layers. In both configurations, the centers of islands on the lower layer are positioned at the gaps between magnetic islands on the upper layer. This achieves the separation of the individual layer signals since the centers of islands in both layers are deliberately misaligned. Moreover, the equalizer design that takes the input data from both layers into consideration is also proposed. Simulation results demonstrate that when employing the same detector, the proposed configurations of the double-layered BPMR systems achieve better performance than the single-layered BPMR system.

Design of gain equalization for multi-core supermode fiber amplifier (inside back cover paper)

Design of gain equalization for multi-core supermode fiber amplifier (inside back cover paper)

Asynchronous Bidirectional Communication in Cell-Free Networks

We consider a bidirectional communication between two single-antenna transceivers using multiple multi-antenna access points (APs) in a cell-free network architecture. In such a network, because of different propagation delays associated with different APs, the end-to-end link is a multi-path channel that results in inter-symbol-interference (ISI) in the signals received at the transceivers. To tackle ISI, we resort to cyclic prefix (CP) assisted block transmission of the information symbols and employ joint pre- and post-channel equalizers at both the transceivers to mitigate the impact of intra-block interference. Considering the amplify-and-forward technique at the APs, we cast the joint design of equalizers, beamforming matrices, and transceivers’ transmit powers as a power minimization problem while guaranteeing predefined data rates at the transceivers. Assuming symmetric beamforming matrices at the APs, we devise a semi-closed-form solution for this problem. We prove rigorously that at the optimum only a synchronous subset of the APs should participate in the information exchange between the two transceivers. This is achieved by proving that at the optimum, the pre-equalizer matrices should be unitary and the post-equalizer matrices should be invertible.

MMSE Equalizer Design Optimization for Wireline SerDes Applications

MMSE Equalizer Design Optimization for Wireline SerDes Applications

Design of a bus-based battery equalization with zero-current switching

A novel any cell to any cell equalization circuit topology with small column, low weight, low cost, and high efficiency is proposed for serial-connected batteries, especially suitable for unmanned aerial vehicles, satellites, and other fields with strict requirements on size, weight, reliability, and safety. To solve the problems of high switching losses in equalization circuits and low reliability of complex control schemes. A half-bridge circuit to convert the DC voltage of the battery into AC voltage is employed, and the energy is exchanged autonomously via the bus. At the same time, LC resonant circuit is used to achieve zero-current switching of the MOSFET, thus reduces greatly the switching losses. The working principle is analyzed by theoretical derivation, and the parameters of the circuit are optimized through circuit simulation. Furthermore, experiments which support six cells equalization are carried out to verify the feasibility and advantage of this topology. This equalization uses a bus-type architecture to improve equalization efficiency and topological flexibility making it even more valuable in the industrial and aerospace fields.

A versatile and high-load soft gripper enabled by vacuum-assisted bio-inspired interfacial adhesion

Abstract Soft robotic grippers have gained considerable attention owing to their highly compliant, adaptive, and safe characteristics in a large variety of scenes, especially involving human-machine interactions. However, the low-stiffness nature of the soft material and the multi-finger gripping mechanism make soft grasping systems suffer in applications requiring relatively high load capacity and broad grasping adaptability. Despite extensive efforts to develop soft grippers with tunable stiffness by constructing smart materials and structures, the resultant load capacity is often compromised by sacrificing working efficiency or surface adaptability. In this work, we report a paradigm to design a versatile, high-load (>2 kg), and fast-response (<1 s) pneumatic soft gripper by strengthening the contact interface via bio-inspired controllable adhesion. A mushroom-shaped micropatterned dry adhesive surface is integrated with a soft pneumatic bidirectionally bendable actuator via a vacuum-assisted equal load-sharing design. This gripper extends the adaptable object diameter from 15 mm to infinity and significantly increases the load capacity to over 2 kg without compromising the original compliance. The multifunctional grasping modes and high load capacity are successfully demonstrated by grasping objects with diverse material components, various surface shapes.

Design of equalizers for frequency selective MIMO systems with low redundancy

In this paper, we propose several designs of filter bank based decision feedback equalizers (DFE) for frequency selective multi-input multi-output (MIMO) systems. Transmission schemes over frequency selective channels are typically block based, and redundancy in form of guard intervals must be used to avoid inter-block interference (IBI). This paper will focus on the case where spectral efficiency demands low levels of redundancy. Then the remaining IBI will be eliminated by a separate feedback loop. The co-channel interference (CCI) inherited in MIMO channels will be eliminated by different DFE schemes. In another approach, a multi-tap MIMO DFE will be designed to deal with both IBI and CCI. The simulation results show that for quasi-static frequency selective MIMO channels, the multi-tap DFE provides the best performance while for Raleigh frequency selective MIMO channels, the dual loop DFE is a good solution for transmission with low redundancy.

Deep Reinforcement Learning-Based Optimal and Fast Hybrid Equalizer Design Method for High-Bandwidth Memory (HBM) Module

Deep Reinforcement Learning-Based Optimal and Fast Hybrid Equalizer Design Method for High-Bandwidth Memory (HBM) Module

Channel State Information Based Equalizer Design for Frequency Selective Channels

Abstract—Equalizer design is an extremely critical aspect for wireless networks. This paper presents an approach combining the decision feedback mechanism and successive signal detection to equalize frequency selective channel effects for signals traversing different run-lengths. In this approach, the errors on comparison between the transmitted signal and received signal are fed to the equalizer to adjust the tap weights. Still the irreversible nature of inter symbol interference is a huge challenge due to multi path propagation mechanisms in wireless channels. It is a common observation that signals traversing a smaller path reach the receiver earlier compared to the multi-path component traversing a longer path. Assuming similar shadowing effects, it is seen that fading effects make it difficult to accurately receive long distance MPCs, thereby degrading the BER performance. It has been shown that the proposed system attains almost similar BER performance irrespective of the shadowing effect or run length of the MPCs. Keywords— Multi Path Component (MPC), Inter Symbol Interference (ISI), Adaptive Equalizer, Channel State Information (CSI), , Bit Error Rate (BER), Probability of Error

Extrinsic information based enhanced Doppler compensation for high-speed underwater acoustic mobile communication

In high-speed underwater acoustic mobile communication, achieving robust Doppler compensation is crucial due to the unpredictable changes in the Doppler factor. Due to the difficulty in optimizing Doppler estimation in turbo equalization through closed-form methods, a joint design of Doppler compensation, channel equalization, and decoding, is proposed to improve the accuracy of the Doppler compensation through integrated methods. Specifically, the proposed scheme utilizes extrinsic information provided by the decoder to evaluate the effectiveness of Doppler compensation because the extrinsic information indirectly reflects the accuracy of Doppler estimation. The proposed algorithm performs parallel Doppler resampling through multiple joint Doppler compensation, equalization, and decoding to optimize Doppler estimation by searching for the best extrinsic information. With iterative Doppler compensation and channel equalization, the accuracy of Doppler estimation is enhanced, leading to improved signal detection performance. The proposed algorithm was verified by underwater test data collected in Qiandao Lake, Hangzhou, China in May 2016. The results of this evaluation provide practical validation and demonstrate the effectiveness of the proposed algorithm in real-world underwater acoustic communication scenarios.

Evidence2Practice (E2P): Leveraging Implementation Science to Promote Careers in HIV Research Among Students From Historically Black Colleges and Universities.

The HIV research workforce is not representative of populations most affected by the epidemic. Innovative educational programs are needed to motivate diverse student populations to pursue careers in HIV research. The Duke University Center for AIDS Research Evidence2Practice (E2P) program is a 3-day interactive workshop that introduces students from Historically Black Colleges and Universities (HBCU) to HIV pre-exposure prophylaxis, implementation science, and human-centered design. Participants develop 1-page action plans to increase awareness and uptake of pre-exposure prophylaxis on their campus. The program was evaluated using a partially mixed-method concurrent equal status study design with pre-program and post-program surveys and in-depth interviews. Among the 52 participating students, 44 completed the preworkshop survey, 45 completed the postworkshop survey, and 10 participated in an in-depth interview. Most participants identified as Black or African American and cisgender female. Participating in the E2P program was associated with: (1) an increase in median interest in pursuing a career in HIV research (P < 0.01) and (2) a decrease in median perceived difficulty in starting a career in HIV research (P < 0.01). Several students described that a lack of knowledge about initiating an HIV research career, a perceived lack of qualifications and knowledge about HIV science, and limited experience were major barriers to considering careers in HIV research. The E2P program enhanced HBCU students' interest in careers related to HIV research and improved their self-efficacy to pursue such careers. On-campus educational enrichment initiatives, led by active HIV researchers and clinicians, should be a critical part of diversifying the HIV workforce.